Battery pack base plate heat exchanger

Abstract

A heat exchanger integrated into an electric vehicle's battery pack enclosure is provided, where the heat exchanger conduits are mechanically and thermally coupled to the inside surface of the enclosure base plate and where the battery pack enclosure is mounted such that ambient air flows over the outside surface of the enclosure base plate during vehicle motion. A thermal management system is coupled to, and controls operation of, the integrated battery pack heat exchanger such that in a first operational mode the heat exchanger is thermally coupled to the batteries within the battery pack, and in a second operational mode the heat exchanger is thermally decoupled from the batteries within the battery pack.

The invention claimed is: 
     
       1. An integrated battery pack heat exchanger system, comprising:
 a battery pack enclosure mounted under an electric vehicle, wherein said battery pack enclosure comprises an enclosure top panel, an enclosure base plate fabricated from a thermally conductive material having a thermal conductivity greater than 1.05 W/m-K, a plurality of enclosure side members, and at least one coolant conduit, wherein said battery pack enclosure is configured to hold a plurality of batteries, wherein said battery pack enclosure is mounted between a passenger cabin floor panel and a driving surface, wherein an outside surface of said enclosure base plate is exposed to an ambient environment outside of said electric vehicle, and wherein ambient air flows past said outside surface of said enclosure base plate during motion of said electric vehicle; 
 a plurality of heat exchanger conduits mechanically and thermally coupled to an inside surface of said enclosure base plate; and 
 a thermal management system coupled to said integrated battery pack heat exchanger system and controlling operation of said integrated battery pack heat exchanger system, wherein said plurality of heat exchanger conduits are thermally coupled, via said at least one coolant conduit, to said plurality of batteries when said thermal management system configures said integrated battery pack heat exchanger system into a first operational mode, and wherein said plurality of heat exchanger conduits are thermally decoupled from said plurality of batteries when said thermal management system configures said integrated battery pack heat exchanger system into a second operational mode. 
 
     
     
       2. The integrated battery pack heat exchanger system of  claim 1 , wherein said plurality of heat exchanger conduits are thermally coupled to at least one of a vehicle traction motor, a transmission, a battery charging system, or a power electronics module when said thermal management system configures said integrated battery pack heat exchanger system into either said first operational mode or said second operational mode. 
     
     
       3. The integrated battery pack heat exchanger system of  claim 2 , further comprising a heat exchanger bypass valve, wherein said heat exchanger bypass valve in a first position thermally couples said plurality of heat exchanger conduits to at least one of said vehicle traction motor, said transmission, said battery charging system, or said power electronics module when said integrated battery pack heat exchanger system is in either said first operational mode or said second operational mode, and wherein said heat exchanger bypass valve in a second position circumvents said plurality of heat exchanger conduits and decouples said plurality of heat exchanger conduits from said vehicle traction motor, said transmission, said battery charging system, or said power electronics module when said integrated battery pack heat exchanger system is in either said first operational mode or said second operational mode. 
     
     
       4. The integrated battery pack heat exchanger system of  claim 1 , further comprising a layer of a thermally insulating material interposed between said plurality of batteries and said plurality of heat exchanger conduits, wherein said layer of said thermally insulating material thermally isolates said plurality of batteries from said plurality of heat exchanger conduits. 
     
     
       5. The integrated battery pack heat exchanger system of  claim 4 , wherein said layer of a thermally insulating material has a thermal conductivity of less than 1.0 W/m-K. 
     
     
       6. The integrated battery pack heat exchanger system of  claim 1 , wherein said plurality of heat exchanger conduits are mechanically and thermally coupled to said inside surface of said enclosure base plate using a coupling technique selected from the group consisting of brazing, soldering, welding and bonding. 
     
     
       7. The integrated battery pack heat exchanger system of  claim 1 , further comprising a blower fan, wherein said blower fan directs air over said outside surface of said enclosure base plate. 
     
     
       8. The integrated battery pack heat exchanger system of  claim 7 , wherein said blower fan is mounted within said electric vehicle, and wherein an air duct directs air flow from said blower fan over said outside surface of said enclosure base plate. 
     
     
       9. The integrated battery pack heat exchanger system of  claim 7 , further comprising at least one slot integrated into said outside surface of said enclosure base plate. 
     
     
       10. The integrated battery pack heat exchanger system of  claim 1 , further comprising a blower fan and at least one closed channel integrated into said outside surface of said enclosure base plate, wherein said blower fan directs air through said at least one closed channel integrated into said outside surface of said enclosure base plate. 
     
     
       11. The integrated battery pack heat exchanger system of  claim 1 , further comprising:
 a first coolant loop coupled to said at least one coolant conduit, said first coolant loop comprising a first circulation pump for circulating a coolant within said first coolant loop; 
 a second coolant loop thermally coupled to said plurality of heat exchanger conduits and to at least one of a vehicle traction motor, a transmission, a battery charging system, or a power electronics module, said second coolant loop comprising a second circulation pump for circulating said coolant within said second coolant loop; and 
 a dual mode valve system coupled to said thermal management system, wherein in said first operational mode said dual mode valve system is configured in a first mode and wherein in said second operational mode said dual mode valve system is configured in a second mode, wherein when said dual mode valve system is configured in said first mode said first coolant loop is serially coupled to said second coolant loop, and wherein when said dual mode valve system is configured in said second mode said first coolant loop operates in parallel with and separate from said second coolant loop. 
 
     
     
       12. The integrated battery pack heat exchanger system of  claim 11 , further comprising a heat exchanger bypass valve integrated into said second coolant loop, wherein said heat exchanger bypass valve controls flow of said coolant through said plurality of heat exchanger conduits. 
     
     
       13. The integrated battery pack heat exchanger system of  claim 11 , wherein said dual mode valve system is comprised of a four-way valve, wherein said four-way valve configured in said first mode couples a first portion of said first coolant loop to a second portion of said second coolant loop and couples a first portion of said second coolant loop to a second portion of said first coolant loop, and wherein said four-way valve configured in said second mode couples said first portion of said first coolant loop to said second portion of said first coolant loop and couples said first portion of said second coolant loop to said second portion of said second coolant loop. 
     
     
       14. The integrated battery pack heat exchanger system of  claim 11 , further comprising a refrigeration subsystem thermally coupleable to said first coolant loop via a refrigeration subsystem heat exchanger. 
     
     
       15. The integrated battery pack heat exchanger system of  claim 14 , wherein said refrigeration subsystem further comprises a refrigerant, a compressor, a condenser and a thermostatic expansion valve. 
     
     
       16. The integrated battery pack heat exchanger system of  claim 14 , further comprising a cabin heating, ventilation and cooling (HVAC) subsystem thermally coupleable to said refrigeration subsystem via said refrigeration subsystem heat exchanger. 
     
     
       17. The integrated battery pack heat exchanger system of  claim 11 , further comprising a heater thermally coupled to said first coolant loop.